Surgical Instrument Motor With Increased Number Of Wires Per Phase Set And Increased Fill Factor And Corresponding Manufacturing Method

ABSTRACT

A motor for a surgical instrument includes a rotor and a stator. The rotor includes a shaft and a magnet. The stator includes (i) a cavity in which the rotor is disposed, and (ii) a coil assembly. The coil assembly includes multiple phase sets. The phase sets include multiple sets of wires. Each of the phase sets includes multiple coils and corresponds to a respective one of the sets of wires. The coils in each of the phase sets are at respective positions about the rotor. One of the sets of wires includes at least three wires. The stator causes the rotor to axially rotate a surgical tool of the surgical instrument based on current received at the sets of wires.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/534,794filed on Nov. 6, 2014. The entire disclosure of the above application isincorporated herein by reference.

FIELD

The present disclosure relates to electric motors of hand-held surgicalinstruments.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent the work is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

A hand-held surgical instrument may have various parameter requirementsincluding weight, power, size, current loss and heat generationrequirements. Producing a hand-held surgical instrument with decreasedweight, increased power output and/or torque, decreased size, reducedcurrent loss and decreased heat generation can be difficult due to therelationships between these parameters. For example, as power output ofa motor increases, heat generated by the motor generally increases. Asanother example, as size of a motor decreases, power output of the motortypically decreases.

A brushless direct current (DC) motor is capable of operating at higherefficiency levels and at higher speeds with reduced heat generation thana motor with brushes due to no mechanical contact between rotating andstationary components of the brushless DC motor. A brushless DC motorcan include a rotor and a stator. The rotor has a shaft and a hubassembly with a centrally located magnetic structure. The stator has oneor more coils. The coils are mounted on a centrally located supportsleeve and proximally and distally located support rings. The rotor isheld in a cavity of the stator and in a position relative to the supportsleeve and support rings such that the rotor does not contact thesupport sleeve, the coils, and/or the support rings. Electrical currentis supplied to the coils, which causes the rotor to rotate relative tothe stator due to interactions between (i) magnetic fields generated bythe coils and (ii) a magnetic field produced by the magnetic structureof the rotor. The rotor rotates axially in the support sleeve, thecoils, and the support rings.

Brushless DC motors (hereinafter referred to as “motors”) convertelectrical power into mechanical power or torque. During thisconversion, losses can arise that limit mechanical power, torque andspeed of the motors. These losses can generally be classified into threecategories: (1) load sensitive losses dependent on generated torque; (2)speed sensitive losses dependent on motor speed; and (3) pulse-widthmodulation (PWM) losses dependent on quality of a current supplyemployed to drive the motors.

The load or torque sensitive losses are generally limited to windinglosses, which are proportional to a product of (i) a square of an amountof current through windings of a motor and (ii) a resistance of thewindings. Speed sensitive losses (e.g., core or iron losses due to Eddycurrents and hysteresis, windage and friction) act as a velocitydependent torque opposite an output torque of a motor. PWM losses areattributable to Eddy currents in a magnetic structure caused by thecurrent supply. Eddy currents are a phenomena caused by a variation of amagnetic field through an electrically conductive medium. In the case ofbrushless DC motors, the coils of the stator experience a change in amagnetic field. The rotation of the rotor and current variations in thecoils induce a voltage in the coils, which results in the creation ofEddy currents. Increased Eddy currents can increase thermal energyoutput of a motor, especially when operating at high speeds.

SUMMARY

A motor for a surgical instrument is provided and includes a rotor and astator. The rotor includes a shaft and a magnet. The stator includes (i)a cavity in which the rotor is disposed, and (ii) a coil assembly. Thecoil assembly includes multiple phase sets. The phase sets includemultiple sets of wires. Each of the phase sets includes multiple coilsand corresponds to a respective one of the sets of wires. The coils ineach of the phase sets are at respective positions about the rotor. Oneof the sets of wires includes at least three wires. The stator causesthe rotor to axially rotate a surgical tool of the surgical instrumentbased on current received at the sets of wires.

In other features, a method of manufacturing a motor for a surgicalinstrument is provided. The method includes: providing a rod withmultiple sets of pins; and wrapping multiple sets of wires on the setsof pins to form multiple phase sets on the rod to provide a coil body.Each of the phase sets includes multiple coils and corresponds to arespective one of the sets of wires. The method further includes:removing the sets of pins from the rod; compressing the coil body afirst time; inserting a portion of the coil body in a sleeve; connectingthe phase sets in series; applying current to the phase sets to fuse thesets of wires a first time; compressing the coil body a second time;applying current to the phase sets to fuse the sets of wires a secondtime; removing the coil body from the rod; and inserting the coil bodyinto a motor housing of the surgical instrument.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective environmental view of a surgical instrumentincorporating a brushless sensorless DC motor in accordance with anembodiment of the present disclosure.

FIG. 2 is a side perspective view of a portion of the surgicalinstrument of FIG. 1.

FIG. 3 is a side exploded view of a portion of the surgical instrumentof FIG. 1.

FIG. 4 is an axial cross-sectional view of a motor and a portion of amotor housing in accordance with an embodiment of the presentdisclosure.

FIG. 5 is a radial cross-sectional view of a multi-phase set coilassembly of a motor in accordance with an embodiment of the presentdisclosure.

FIG. 6 is a sectional view of compressed and fused wires of coils of amotor in accordance with an embodiment of the present disclosure.

FIG. 7 illustrates a method of constructing a multi-phase set coilassembly of a motor in accordance with an embodiment of the presentdisclosure.

FIG. 8 is a side perspective view of a mandrel having a separation layerin accordance with an embodiment of the present disclosure.

FIG. 9 is a perspective view of a portion of the mandrel illustratingsets of pins inserted in the mandrel in accordance with an embodiment ofthe present disclosure.

FIG. 10 is a side perspective view of the mandrel mounted on a rotatingdevice in accordance with an embodiment of the present disclosure.

FIG. 11 is a block and side perspective view of a wire delivery systemillustrating placement of wires relative to the mandrel and some of thepins in accordance with an embodiment of the present disclosure.

FIG. 12 is a perspective view illustrating wrapping wires of a firstcoil of a first phase set of the multi-phase set coil assembly inaccordance with an embodiment of the present disclosure.

FIG. 13 is a perspective view illustrating wrapping wires of a secondcoil of the first phase set of the multi-phase set coil assembly of FIG.12.

FIG. 14 is a side perspective view of the multi-phase set coil assemblymounted on the mandrel in accordance with an embodiment of the presentdisclosure.

FIG. 15 is a perspective environmental view illustrating heat strippingand coating of ends of sets of wires of the multi-phase set coilassembly in accordance with an embodiment of the present disclosure.

FIG. 16 is a perspective view of the multi-phase set coil assemblymounted on the mandrel without a set of pins and in accordance with anembodiment of the present disclosure.

FIG. 17 is a perspective view of the multi-phase set coil assemblymounted on the mandrel having a portion of the multi-phase coil assemblywrapped and compressed in accordance with an embodiment of the presentdisclosure.

FIG. 18 is a perspective view of the multi-phase set coil assemblymounted on the mandrel having a second set of pins removed in accordancewith an embodiment of the present disclosure.

FIG. 19 is a perspective view of the multi-phase set coil assemblymounted on the mandrel having a second portion of the multi-phase setcoil assembly wrapped and compressed in accordance with an embodiment ofthe present disclosure.

FIG. 20 is a perspective view of the multi-phase set coil assemblymounted on the mandrel illustrating a thermocouple and a holding layerover a center of the multi-phase set coil assembly in accordance with anembodiment of the present disclosure.

FIG. 21 is a perspective view of the multi-phase set coil assemblymounted on the mandrel illustrating a protection layer being appliedover a center portion of the multi-phase set coil assembly in accordancewith an embodiment of the present disclosure.

FIG. 22 is a perspective view of the multi-phase set coil assemblymounted on the mandrel illustrating a portion of the multi-phase setcoil assembly inserted in a sleeve in accordance with an embodiment ofthe present disclosure.

FIG. 23 is a perspective view of the multi-phase set coil assembly, themandrel, and the sleeve inserted in a base of a press in accordance withan embodiment of the present disclosure.

FIG. 24 is a perspective view of the press in a closed fully compressedstate in accordance with an embodiment of the present disclosure.

FIG. 25 is a cross-sectional view of a wire in accordance with anembodiment of the present disclosure.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DESCRIPTION

Surgical instruments are disclosed below that include brushlesssensorless DC motors. The brushless sensorless DC motors have increasedpower output and/or torque, reduced current losses including Eddycurrent losses, reduced coil resistances, increased fill factors (orcoil slot fill levels), and reduced heat generation than motors oftraditional surgical instruments. These features are provided withoutincreasing overall exterior dimensions of the brushless sensorless DCmotors. These features are provided while reducing a number of statorsupport components and thus simplifying an interior of a motor housing.Example methods are also disclosed for manufacturing the brushlesssensorless DC motors.

FIG. 1 shows a surgical instrument 10 incorporating a brushlesssensorless DC motor 12 (hereinafter referred to as “the motor”). Thesurgical instrument 10 includes a motor housing 14 that includes themotor 12. Examples of the motor 12 are shown in at least FIG. 4. Thesurgical instrument 10 may be used, for example, to mill, drill, shapeand dissect bone and other tissue. The surgical instrument 10 is shownoperatively associated with a patient 16. As an example, the surgicalinstrument 10 may be used to perform various procedures (e.g., acraniotomy). The surgical instrument 10 is not limited to any particularsurgical procedures and/or applications. These applications may includedissecting bone or other tissue. Additional example applicationsinclude: 1) arthroscopy—orthopaedic applications; 2)endoscopic—gastroenterology, urology, and soft tissue applications; 3)neurosurgery—cranial, spine, and otology applications; 4) smallbone—orthopaedic, oral-maxiofacial, ortho-spine, and otologyapplications; 5) cardio thoracic—small bone sub-segment applications; 6)large bone—total joint and trauma applications; and 7) dentalapplications.

FIGS. 2-3 show portions 20, 22 of the surgical instrument 10 of FIG. 1.The surgical instrument 10 includes a collet 24, the motor housing 26, aconnector 28, and a cable 30. The collet 24 is configured to hold asurgical tool (e.g., surgical tool 32 is shown in FIG. 1). The surgicaltool may be a cutting tool and/or dissection tool (e.g., a tool thatincludes a surgical bur). The motor housing 26 connects to the collet 24and the cable connector 28. The motor 12 is mounted in the motor housing26 and axially rotates the surgical tool based on power, current and/orvoltage supplied to the motor via the cable 30. A portion of thesurgical tool may extend through the collet and connect to a shaft ofthe motor. An example shaft is shown in FIG. 4. In operation, the motor12 provides torque to axially rotate (or spin) the surgical tool.

FIG. 4 shows an axial cross-sectional view of (i) a portion 40 of themotor housing 26 of FIGS. 2-3, and (ii) the motor 12. The motor housing26 includes laminations 42. The laminations 42 are cylindrically-shapedand are mounted on interior walls 44 of the motor housing 26 adjacentand opposing one or more magnets 58 (or a center portion 46 of the motor12). The laminations 42 channel, direct or steer a magnetic fieldgenerated by the one or more magnets 58 and electrical currents in acoil body 48 away from the housing 26. This directs magnetic fluxprovided by the magnetic field of the one or more magnets 58 through thecoil body 48 of the motor 12, as opposed to the magnetic flux beingreceived by the motor housing 26. The motor 12 includes a rotor 50 and astator 52.

The rotor 50 includes a shaft 56 on which the one or more magnets 58 aremounted. The shaft 56 may be connected to a surgical tool (e.g., thesurgical tool 32 of FIG. 1). The surgical tool may be axially rotatedbased on axial rotation of the shaft 56. The shaft 56 and the magnets 58are axially rotated within the stator 52. The one or more magnets 58 mayinclude, for example, high-energy density rare-earth magnetic materials.A press ring 60 may be mounted on the shaft 56 and incorporated tobalance spinning motion of the shaft 56. The shaft may ride on bearingsets (not shown) proximally and distally located in the motor housing26.

The stator 52 may include the coil body 48 (sometimes referred to as amulti-phase set coil assembly) with a predetermined number of coils(e.g., six coils or two coils per phase set). Examples of the coils areshown in FIGS. 5-6, 13-14, and 16-23. Although the motors disclosedherein are primarily described with respect to a 3-phase set coilassembly having 6 coils, the motors may have any number of phase setsand/or coils per phase set. A 3-phase set refers to coils of each phaseset being at respective axial phases (or axial positions) around therotor 50. Each of the phase sets may be at 120° intervals around therotor 50. As shown in FIG. 4, the stator 52 includes the coil body 48and does not include proximal, central and/or distally located supportmembers. This is due to the rigid structure of the coil body 48, whichis further described below. The coil body 48 is held in place within thelaminations 42 and the interior walls 44. This is unlike traditionalcoil bodies that have proximal, central and distal support members(e.g., support rings extending within the coil bodies).

The coil body 48 has a distal end 62 and a proximal end 64. Although notshown in FIG. 4, sets of wires extend from the proximal end 64 andreceive power from a power source via a cable (e.g., the cable 30 ofFIG. 3). The sets of wires are shown in FIGS. 14, 16-22 and 24. Theproximal end 64 may be held between the motor housing 26. The coil body48 and thus the coils of the coil body 48 are sized to fill ahigh-percentage of a cavity 70 of the coil body 48 between thelaminations 42 and the magnets 58 while not contacting the laminations42 and the magnets 58. A first gap G1 exists between the laminations 42and the coil body 48 and may be filled with a dielectric material forelectric isolation. A second gap G2 (or air gap) exists between the coilbody 48 and the magnets 58. A first inner diameter D1 of the coil body48 at the distal end 62 may be, for example, 6-6.5 millimeters (mm). Asecond inner diameter D2 of the coil body 48 in the center portion 46and opposing the magnets 58 may be, for example, 7-8.2 millimeters (mm).A first outer diameter D3 of the coil body 48 in the center portion 46may be, for example, 10-11 mm. A second outer diameter D4 of the coilbody 48 at the proximal end 64 may be, for example, 12-14 mm.

FIGS. 5-6 show radial cross-sectional views of a coil body (ormulti-phase set coil assembly) 80 of a motor (e.g., the motor 12 of FIG.1). The coil body includes multiple coils and may replace the coil body48 of FIG. 4. Each coil of the coil body includes sets of wires. Some ofthe wires are designated 82. Each of the wires includes a conductivefilament and a thin outer insulation layer to prevent electricalconnections between the wires. The number of wires in each of the setsof wires and cross-sectional diameters (an example cross-sectionaldiameter D5 is shown in FIG. 6) of the wires affects a fill factor ofthe coil body. The fill factor refers to a percentage of conductivematerial (e.g., copper) contained within a volume (or envelope) of thecoil body. An example cross-sectional view of a wire 90 including afilament 92, an insulation layer 94 and a bonding layer 96 is shown inFIG. 25.

The higher the fill factor, the more conductive material within a givenarea. Also, the higher the fill factor or the more conductive materialper set of wires, the lower the resistances of the sets of wires. Ingeneral, the more conductive material, the more power output and/ortorque produced by a corresponding motor. Also, as the number of wiresper set increases, for a given fill factor, the amount of Eddy currentlosses decreases. On the other hand, as the fill factor increases, theamount of Eddy current losses increases. In addition, there arestructural and manufacturing limits as to how small a cross-sectionaldiameter of the wires can be and how many wires can be manufactured,handled, and wrapped, to form the coils. For example, the smaller thecross-sectional diameter of the wires, the more likely that the wiresare deformed during manufacturing. The smaller the cross-sectionaldiameter of each of the wires, the more wires can be wrapped to fill agiven volume. Although the more wires the lower the fill factor. This isdue to the volume associated with the insulation layers of the wires.

Thus, to maximize power and torque output of a motor, minimize size ofthe motor, minimize current losses, prevent deforming of wires of themotor, and assure the motor is an efficient and structurally reliablemotor, certain parameters of a coil body are selected to be withinpredetermined ranges. In addition, the coil body is constructed tominimize number of coil supports and to maximize a fill factor for agiven volume of the coil body. As a first example, each set of wires mayinclude a predetermined number of wires (e.g., 10-20 wires). In oneembodiment, each of the sets of wires includes 15-18 wires. In anotherembodiment, each of the sets of wires includes 17-18 wires. As anotherexample, the cross-sectional diameter of the wires may be 0.09-0.14 mm.As yet another example, a combined thickness of an insulation layer anda bonding (or adhesive) layer of each of the wires may be, for example,10-20 micrometers (μm). Each of the wires has an insulation layer andmay have a bonding (or adhesive layer). The purpose of these layers isfurther described below. An example cross-sectional diameter D6 of thewire 90 and a corresponding combination thickness T1 of the insulationlayer 94 and the bonding layer 96 are shown in FIG. 25.

In one embodiment, the wires are 38 American wire gauge (AWG38) wires,where a combination thickness of an insulation layer and a correspondingbonding layer of each of the wires is 15 μm. As still another example,the fill factor may be (i) 58-65% if bonding layers or a bonding agentis used, or (ii) 66-74% if bonding layers or a bonding agent is used. Abonding agent or varnish may be applied to the insulation layers toprovide the bonding layers.

Incorporating sets of wires, where each of the sets of wires has anumber of wires within a predetermined range (e.g., 15-18) and thecross-sectional diameters of the wires are within a second predeterminedrange (e.g., 0.10-0.12 mm), provides a fill factor with an increasedlevel of conductive material, reduced phase set resistances, reducedcurrent losses, and as a result reduced heat generated. This isespecially true during high-load and/or high-speed operating conditions.Under low-load and/or low-speed operating conditions, Eddy currentlosses are minimized by providing a motor with numbers of wires, in eachof the sets of wires, being in one of the predetermined ranges. Eddycurrent losses increase as fill factor increases.

The sets of wires are compressed and fused to each other, as furtherdescribed below with respect to the method of FIG. 7, to increase a fillfactor of the coils. A bonding agent may be applied to the wires priorto and/or during wrapping, compressing and/or fusing tasks associatedwith manufacturing of the coil body. The bonding agent may be used toaid in fusing the wires together to provide a rigid structure that hasminimal flex during high-speed spinning. In one embodiment, a bondingagent is not used. The compression and fusing of the wires allows forthe coil body not to be supported centrally and/or at proximal and/ordistal ends by support members. Removal of proximal, distal andcentrally located support members allows for additional conductivematerial to be incorporated in a same size volume. This allows foradditional wrappings of the wires and/or an increased number of wiresper set of wires to be used in the coils of the coil body.

The coil bodies (or coil assemblies) disclosed herein may bemanufactured using the method of FIG. 7. FIG. 7 shows a method ofconstructing a multi-phase set coil assembly of a motor. Although thefollowing tasks are primarily described with respect to theimplementations of FIGS. 1-6, the tasks may be easily modified to applyto other implementations of the present disclosure. The tasks may beiteratively performed.

The method may begin at 200. At 202, a press 100 (shown in FIG. 24) ispre-heated to a predetermined temperature for a predetermined period.The press 100 may be in a form of a clam shell having a base 102 (orclam shell bottom) and a compression block 104 (or clam shell top). Thepredetermined temperature may be, for example 200° C. The predeterminedperiod may be, for example, 2 hours.

At 204, a separation layer 106 may be applied to a lubricated mandrel108 (or other lubricated cylindrical rod), as shown in FIG. 8. In oneembodiment, step 204 is skipped and the separation layer 106 is notapplied to the mandrel 108. The mandrel 108 may be cylindrically shapedand include two sets of holes 110, 112. Each of the sets of holesincludes a predetermined number of holes (e.g. 6 holes per set). Theholes 110, 112 in each of the sets of holes 110, 112 are evenlydistributed around the mandrel 108 at 60° increments (or intervals).Each set of holes may be perpendicular to a central longitudinal axis ofthe mandrel 108 or at other angles (e.g. 30-60° degrees) relative to thecentral longitudinal axis such that the holes angle outward towardproximal and/or distal ends of the mandrel 108. The separation layer 106may be applied to the mandrel 108 with an adhesive side of theseparation layer 106 facing outward away from the mandrel 108 and anon-adhesive side of the separation layer 106 facing the mandrel 108. Asan example, the separation layer 106 may include a polyimide film layerand an adhesive layer. The adhesive layer providing the adhesive side ofthe separation layer 106.

At 206, two sets of pins 118, 120 are inserted in the holes 110, 112 inthe mandrel 108. This includes puncturing holes in the separation layer106 at the holes 110, 112 in the mandrel 108. FIG. 9 shows the pins 118,120 in the holes 110, 112. The pins 118, 120 while in the holes 110, 112extend radially outward and provide wrapping points for sets of wires,as further described below.

At 208, the mandrel 108, with the separation layer 106 and the pins 118,120, is mounted on a rotating device 130 via a mounting bracket 132. Asan example, the rotating device 130 may include a motor 134, a rotarychuck 136, a control module 138 and a counter 140, as shown in FIG. 10.The mandrel 108 is held by the mounting bracket 132, which is rotatedvia the rotary chuck 136. The mandrel 108 may be connected to themounting bracket 132 via a screw 142 that extends through a portion ofthe mounting bracket 132 and into a first end 144 of the mandrel 108.The motor 134 may spin the rotary chuck 136. This may be controlled bythe control module 138 and based on a count indicated by the counter140. The control module 138 may radially rotate the mandrel 108 apredetermined number of times when forming each coil of a coil assembly.The control module 138 may stop rotating the mandrel 108 when thecounter 140 reaches the predetermined number of times. This rotation isperformed as described below at 212.

At 210, a first (or current) set of wires (e.g., wires 148) are groupedtogether and aligned with two pins 150, 152 (one pin from each of thesets of pins 118, 120) on the mandrel 108. An example of this is shownin FIG. 11. FIG. 11 shows a wire delivery system 154. The wire deliverysystem 154 is provided as an example and may be replaced with anotherwire delivery system. The wire delivery system 154 includes spools 156,spool tensioners 158, and a support bracket 160. A first end 161 of thewires may be knotted together to provide a knot 162 and held via, forexample, tape 164 to the first end 144 of the mandrel 108. The first end161 of the wires may be labeled “x in” with a tag to indicate that thisis an input end (or end that receives power) in the current set ofwires, where x identifies the number of the sets of wires to be includedin the coil assembly. The wires may be wound respectively on the spools156 and extend from the spools 156 to the mandrel 108, where the wiresare then grouped together and knotted as shown.

The spools 156 may be mounted on the support bracket 160. Each of thespools 156 may have and/or be connected respectively to the spooltensioners 158 to provide uniform and/or predetermined levels of tensionon the wires. In one embodiment, the spool tensioners 158 provide a sameamount of tension on each of the wires. In another embodiment, the spooltensioners 158 provide different levels of tension on the wires. Thespool tensioners 158 may be connected to the spools via respectiveshafts 166. In addition or as an alternative to the spool tensioners158, post-spool tensioners 157 may be used to “squeeze” down on thewires as the wire comes off the spool. The post-spool tensioners 157 maybe located between the spools and the mandrel 108. Friction provided bythe squeezing of the wires provides tension as the wires are pulled offthe spools 156. When the spool tensioners 158 are not used and thepost-spool tensioners 157 are used, the spools 156 are loosely mountedon the support bracket 160 to freely rotate. Although not shown, thepost-spool tensioners 157 may be mounted on and/or supported by thesupport bracket 160. The support bracket may be rigidly held in placerelative to the rotating device 130.

The attaching of the wires on the first end 144 of the mandrel 108 andthe tension on the wires at a second end 168 of the mandrel 108 allowsthe wires to be tightly and uniformly wrapped on the mandrel 108 withoutkinks and/or undesigned bends in the wires. The wires may be held in aparallel extending fashion or may be twisted together. In oneembodiment, the tension on the wires is controlled via the controlmodule 138 of FIG. 10 or other control module connected to the spooltensioners 158.

At 212, the first (or current) set of wires is wrapped around four (orfirst group) of the pins (two of the four pins are in the first set ofpins 118 and the other two pins are in the second set of pins 120). Thetwo pins in each set of pins are 120° apart from each other. The rotarychuck 136 is rotated to radially rotate the mandrel 108 and wrap thewires on the four pins and provide a first coil 170 of a first (orcurrent) phase set of the coil assembly. The wires may be wrapped untilthe counter 140 reaches the predetermined number of times (orpredetermined number of wraps). As an example, the predetermined numberof times may be 18. FIG. 12 shows an example of the wires wrapped on thefour pins.

At 214, the mandrel 108 is rotated axially 180° prior to wrapping asecond coil 172 of the current phase set of the coil assembly. This mayinclude rotating the mandrel 108 counter clockwise as seen from themounting bracket 132 at the first end 144 of the mandrel 108. The wiresare then aligned with a second group of pins.

At 215, the mandrel 108 is radially rotated to wrap the second coil ofthe current phase set of the coil assembly. FIG. 13 shows the secondcoil 172 formed by wrapping the wires around a second group of pins.

At 216, the wires are cut near the second end 168 of the mandrel 108 toprovide a cut (or second) end 176. The second end 176 of the wires maybe knotted and labeled “x out” to indicate that the second end 176 is anoutput end of the current set of wires. FIG. 13 shows the wires cut atthe second end.

At 218, if another phase set of the coil assembly is to be added to themandrel 108, task 220 is performed, otherwise task 222 is performed.Tasks 210-216 may be performed 3 times for a 3-phase set coil assembly.

At 220, the mandrel 108 is rotated axially 120° to begin wrapping of anext phase set of the coil assembly and the counter 140 may be reset.This may be a counter clock wise rotation as seen at the mountingbracket 132 and/or first end 144 of the mandrel 108. Task 220 may beperformed twice for a 3-phase set coil assembly. At the completion oftasks 202-220, multiple (e.g., 3) phase sets of coils may have beenformed. Each of the phase sets may be 120° out-of-phase from each other.Each coil of a phase set may be 60° out-of-phase from adjacent coils and180° out-of-phase from the other coil of the same phase set. FIG. 14shows a 3-phase set coil assembly 178 mounted on the mandrel 108 aftercompletion of tasks 202-220.

At 222, the ends of the sets of wires are (i) stripped (by heat,chemicals or mechanical devices depending on the type of insulation usedon the wire) to remove insulation layers from the ends of the wires, and(ii) coated. The ends of the set of wires may be heated to apredetermined temperature (e.g., 400° C.) to remove the insulationlayers at the ends of the sets of wires. The insulation layers are notremoved from the remainder of the sets of wires. The coating of the endsmay include tinning the ends. In one embodiment, the ends of the sets ofwires are dipped in a solder bath to coat and bind together theconductive filaments exposed due to the heat stripping. In oneembodiment, the heat stripping and the coating are performed at the sametime. A temperature of the coating material may be high enough (greaterthan or equal to a predetermined temperature) to remove the insulationlayers and at the same time coat the ends of the sets of wires. FIG. 15shows a solder bath 180 and coated ends 179 of sets of wires 184. In analternative embodiment, the stripping and coating of the sets of wires184 change a bit such that no knots in the wires are created. In oneembodiment, the ends 179 of each of the sets of the wires 184 are heldtogether via terminations (or connectors). The terminations may beconnected to a printed circuit board (PCB). As another alternative, thesets of wires 184 may terminate at the PCB.

At 224, a set of the pins (e.g., the second set of pins 118) (thisconflicts with numbering in FIG. 9 where 120 is towards long side ofmandrel) is removed from the second end 168 of the mandrel 108 and afirst portion 181 of the coils are wrapped and compressed. FIG. 16 showsthe second set of pins 118 removed. The other set of pins (i.e. thefirst set of pins 120) remains in the mandrel 108. The first portion 181of the coils may extend from a center 182 of the coils along the mandrel108 to a distal end 183 of the coils. The first portion 181 may bewrapped, for example with a first portion 184 of a first protectionlayer and then compressed via a cable tie 185 (or tie wrap). The firstportion 181 of the first protection layer may include paper. The cabletie 185 may be placed over the paper and around the first portion 181 ofthe coils and pulled tight to hold in place and compress the firstportion 181 of the coils. FIG. 17 shows the first portion 181 wrappedand compressed.

At 226, the other set of the pins (e.g., the first set of pins 120) isremoved from the first end 144 of the mandrel 108 and a second portion186 of the coils are wrapped and compressed. FIG. 18 shows the first setof pins 120 removed. The second portion 186 of the coils may extend fromthe center 182 of the coils along the mandrel 108 to a proximal end 187of the coils. The second portion 186 may be wrapped, for example with asecond portion 188 of the first protection layer and then compressed viaa second cable tie 189. The second portion 188 of the first protectionlayer may include paper. The second cable tie 189 may be placed over thepaper and around the second portion 186 of the coils and pulled tight tohold in place and compress the second portion 186 of the coils. FIG. 19shows the second portion wrapped and compressed.

At 228, resistances are measured. The resistances (e.g., R1, R2, and R3for a 3-set coil assembly) of each of the phase sets may be measured. Atotal resistance Rtot of the phases connected in series may be measured.Resistances between the phase sets may be measured. Resistances (e.g.,R1m, R2m, R3m, where 1, 2, and 3 are phase set numbers and m refers tothe mandrel) between each of the phase sets and the mandrel 108 may alsobe measured. The stated resistances may be measured for referencepurposes and later verified to check whether the phase sets have beendamaged during tasks 230-246 and/or to monitor changes in theresistances due to performing tasks 230-246.

At 230, the first protective layer and the cable ties 185, 189 areremoved from the coils. At 231, a holding layer 190 is applied to acenter portion and over an exterior (or outer surface) of the coils tohold the coils in place. The holding layer 190 may include a polyimidefilm. This is shown in FIG. 20.

At 232, a thermocouple 192 and a second protection layer 193 is appliedto the coils (or coil body 194). The thermocouple 192 is applied tomonitor a temperature of the coils during compression and/or fusing ofthe coils, as performed in the following tasks. The second protectionlayer 193 may include a polyimide film and prevent scraping of the wiresof the coils. As an example, the temperature may be monitored by thecontrol module 138 of FIG. 10 or by another control module. In thefollowing tasks, if the temperature, as indicated by the thermocouple192, exceeds a predetermined temperature, compression and/or fusing maybe stopped and/or current applied to the coils may be decreased. Powerand/or current supplied to the coils may be provided via a power source233 (shown in FIG. 10), which may be controlled via the control module138 or other control module. The power source 233 may be directlyconnected to the coils or may be connected to the coils via the controlmodule.

The thermocouple 192 may be applied to any part of the coils and/orconnected to the control module 138 (or other control module). Thethermocouple 192 may be applied to the proximal end of the coil body 194to not interfere with compression of the coil body 194 during thefollowing tasks. The thermocouple 192 may be applied during task 231 orduring another task. More than one thermocouple may be applied andmonitored.

FIG. 21 shows the second protection layer 193 applied on the distaland/or center portions of the coils. FIG. 22 shows the second protectivelayer 193 applied to (i) distal and center portions of the coils, and(ii) a portion of the proximal portion of the coils. Although not shown,the second protection layer may cover all of the proximal portion of thecoils. The second protective layer 193 is applied over an exterior (orouter surface) of the coils.

At 234, the distal and center portions of the coils and the first end144 of the mandrel 108 are slid into a sleeve. The sleeve may be‘C’-shaped and formed of, for example, stainless steel. The sleeve maybe positioned on the coils based on final predetermined dimensions ofthe coils. As an example, the sleeve may be slid up to the proximal end(or proximal portion) of the coil and not slide over the proximal end ofthe coils. This is because the proximal end of the coils may not becompressed or may be minimally compressed during the following tasks.Thus, the proximal end of the coils may have a larger outer diameterthan outer diameters of the distal and center portions of the coils.This may be based on interior dimensions in a motor housing in which thecoils are to be placed. Applying of the sleeve may at least partiallycompress the distal and center portions of the coils. FIG. 22 shows anexample of a ‘C’-shaped sleeve 195 on distal and center portions ofcoils.

At 236, the phase sets are connected in series and a predeterminedamount of current is applied to the phase sets to pre-fuse the wirestogether. As an example, 20 amperes (A) of DC current may be applied tothe phase sets to heat and fuse the wires.

At 238, the coils, the sleeve, and the mandrel 108 are placed in and/orpushed in the base 102 of the press 100. The sleeve may be placed in thebase 102, such that an opening (or mouth) 239 of the sleeve faces upwardand/or out of the base 102 and can be seen from a top of the base 102.This is shown in FIG. 23. Some of the inner dimensions of the base 102match or are similar to outer dimensions of the coils and sleeve. Thebase 102 may be clam-shaped or ‘C’-shaped, as shown, and has an openingthrough which the coils, sleeve, and mandrel 108 are provided. Due totask 236, a temperature of the coils, sleeve and/or mandrel 108 may begreater than a predetermined temperature when placed in the base 102.

At 240, the compression block 104 of the press is placed in the openingof the base 102 and over the coils, sleeve, and mandrel 108. Some of theinner dimensions of the compression block 104 may match or be similar toexterior dimensions of the coil body. Pressure is applied on thecompression block 104 and thus to the sleeve to compress the coils. Thecompression block 104 may be pushed down into the base 102 until a topsurface 196 of the compression block 104 is (i) above a top surface 197of the base 102 by a first predetermined amount, (ii) flush with the topsurface 197 of the base 102, or (iii) below a top surface 197 of thebase 102 by a second predetermined amount. Pressure on the compressionblock 104 may be increased to a predetermined amount to provide apredetermined amount of compression. FIG. 24 shows the press 100 withthe compression block 104 over the coils, sleeve, and mandrel 108 and inthe base 102. The second end 168 of the mandrel 108 and the ends of thesets of wires extend out of an opening 198 on one side 199 of the press.

At 241, the coils are fused a second time. Current is applied to thephase sets. The phase sets may be connected in series as in task 236and/or may still be connected in series from task 236. A DC current isapplied to the phase sets to heat the wires to a predeterminedtemperature. This may be controlled via the control module 138 and/oranother control module. The power may be provided via the power source233. The predetermined temperature may be, for example, 200° C.±10° C.The DC current may be slowly ramped up to a predetermined level ofcurrent at a predetermined rate to provide even heating of the wires.The predetermined level of current and the predetermined temperature maybe maintained for a predetermined period of time.

At 242, the compression block 104 is further pushed down into the base102. The pressure applied to the compression block 104 may be the sameas or greater than the amount of pressure applied at 240. Thecompression block 104 may be pushed down into the base 102 until the topsurface 196 of the compression block 104 is flush with the top surface197 of the base 102 or below a top surface 197 of the base 102 by athird predetermined amount. The third predetermined amount may be thesame as or different than the second predetermined amount.

At 243, if the coils, sleeve and mandrel 108 are to be rotated, task 244may be performed, otherwise task 245 may be performed. At 244, thecompression block 104 may be removed from the base 102 and the coils,sleeve and/or mandrel 108 may be axially rotated in the base 102. Task234 may be performed subsequent to task 244.

Tasks 234-244 may be repeated a predetermined number of times, such thatthe coils, sleeve and/or mandrel 108 are rotated and compressed thepredetermined number of times to provide an even amount of compressionon the coils such that the coil body has a round exterior dimension.Each rotation of the coils may include axially rotating the sleeve onthe coils.

At 245, the compression block 104 is removed from the base 102 and thecoils, sleeve and mandrel 108 are removed from the press 100. At 246,the sleeve is removed from the coils and the coils are removed from themandrel 108. This may include removing the one or more thermocouples andthe second protective layer 193 from the coil body 194. The coils may betwisted to unstick the coils from the mandrel.

At 248, the resistances measured at 228 may be remeasured and comparedwith the resistances measured at 228. If the resistances measured thesecond time are out of predetermined ranges from the correspondingresistances measure the first time, then one or more of the wires and/orcoils may be damaged. The resistances may be measured prior to removalof the coils from the mandrel 108 in order to obtain the resistancesbetween the phase sets and the mandrel 108 (e.g., the resistances R1m,R2m and R3m). At 248, dimensions of the coil body 194 may be measuredand compared with predetermined dimensions to assure that the coil body194 is within predetermined ranges of the predetermined dimensions. Thismay include measuring lengths, outer diameters, and inner diameters ofthe coil body 194. The method may end at 250.

The above-described tasks are meant to be illustrative examples; thetasks may be performed sequentially, synchronously, simultaneously,continuously, during overlapping time periods or in a different orderdepending upon the application. Also, any of the tasks may not beperformed or skipped depending on the implementation and/or sequence ofevents.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. As used herein, the phrase atleast one of A, B, and C should be construed to mean a logical (A OR BOR C), using a non-exclusive logical OR, and should not be construed tomean “at least one of A, at least one of B, and at least one of C.” Itshould be understood that one or more steps within a method may beexecuted in different order (or concurrently) without altering theprinciples of the present disclosure.

In this application, including the definitions below, the term ‘module’or the term ‘controller’ may be replaced with the term ‘circuit.’ Theterm ‘module’ may refer to, be part of, or include: an ApplicationSpecific Integrated Circuit (ASIC); a digital, analog, or mixedanalog/digital discrete circuit; a digital, analog, or mixedanalog/digital integrated circuit; a combinational logic circuit; afield programmable gate array (FPGA); a processor circuit (shared,dedicated, or group) that executes code; a memory circuit (shared,dedicated, or group) that stores code executed by the processor circuit;other suitable hardware components that provide the describedfunctionality; or a combination of some or all of the above, such as ina system-on-chip.

The module may include one or more interface circuits. In some examples,the interface circuits may include wired or wireless interfaces that areconnected to a local area network (LAN), the Internet, a wide areanetwork (WAN), or combinations thereof. The functionality of any givenmodule of the present disclosure may be distributed among multiplemodules that are connected via interface circuits. For example, multiplemodules may allow load balancing. In a further example, a server (alsoknown as remote, or cloud) module may accomplish some functionality onbehalf of a client module.

The term code, as used above, may include software, firmware, and/ormicrocode, and may refer to programs, routines, functions, classes, datastructures, and/or objects. The term shared processor circuitencompasses a single processor circuit that executes some or all codefrom multiple modules. The term group processor circuit encompasses aprocessor circuit that, in combination with additional processorcircuits, executes some or all code from one or more modules. Referencesto multiple processor circuits encompass multiple processor circuits ondiscrete dies, multiple processor circuits on a single die, multiplecores of a single processor circuit, multiple threads of a singleprocessor circuit, or a combination of the above. The term shared memorycircuit encompasses a single memory circuit that stores some or all codefrom multiple modules. The term group memory circuit encompasses amemory circuit that, in combination with additional memories, storessome or all code from one or more modules.

The term memory circuit is a subset of the term computer-readablemedium. The term computer-readable medium, as used herein, does notencompass transitory electrical or electromagnetic signals propagatingthrough a medium (such as on a carrier wave); the term computer-readablemedium may therefore be considered tangible and non-transitory.Non-limiting examples of a non-transitory, tangible computer-readablemedium are nonvolatile memory circuits (such as a flash memory circuit,an erasable programmable read-only memory circuit, or a mask read-onlymemory circuit), volatile memory circuits (such as a static randomaccess memory circuit or a dynamic random access memory circuit),magnetic storage media (such as an analog or digital magnetic tape or ahard disk drive), and optical storage media (such as a CD, a DVD, or aBlu-ray Disc).

The apparatuses and methods described in this application may bepartially or fully implemented by a special purpose computer created byconfiguring a general purpose computer to execute one or more particularfunctions embodied in computer programs. The functional blocks andflowchart elements described above serve as software specifications,which can be translated into the computer programs by the routine workof a skilled technician or programmer.

The computer programs include processor-executable instructions that arestored on at least one non-transitory, tangible computer-readablemedium. The computer programs may also include or rely on stored data.The computer programs may encompass a basic input/output system (BIOS)that interacts with hardware of the special purpose computer, devicedrivers that interact with particular devices of the special purposecomputer, one or more operating systems, user applications, backgroundservices, background applications, etc.

The computer programs may include: (i) descriptive text to be parsed,such as HTML (hypertext markup language) or XML (extensible markuplanguage), (ii) assembly code, (iii) object code generated from sourcecode by a compiler, (iv) source code for execution by an interpreter,(v) source code for compilation and execution by a just-in-timecompiler, etc. As examples only, source code may be written using syntaxfrom languages including C, C++, C#, Objective C, Haskell, Go, SQL, R,Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5,Ada, ASP (active server pages), PHP, Scala, Eiffel, Smalltalk, Erlang,Ruby, Flash®, Visual Basic®, Lua, and Python®.

None of the elements recited in the claims are intended to be ameans-plus-function element within the meaning of 35 U.S.C. § 112(f)unless an element is expressly recited using the phrase “means for,” orin the case of a method claim using the phrases “operation for” or “stepfor.”

What is claimed is:
 1. A method of manufacturing a motor for a surgicalinstrument, the method comprising: providing a rod with a plurality ofsets of pins; wrapping a plurality of sets of wires on the plurality ofsets of pins to form a plurality of phase sets on the rod to provide acoil body, wherein each of the plurality of phase sets comprises aplurality of coils and corresponds to a respective one of the pluralityof sets of wires; removing the plurality of sets of pins from the rod;compressing the coil body a first time; inserting a portion of the coilbody in a sleeve; connecting the plurality of phase sets in series;applying current to the plurality of phase sets to fuse the plurality ofsets of wires a first time; compressing the coil body a second time;applying current to the plurality of phase sets to fuse the plurality ofsets of wires a second time; removing the coil body from the rod; andinserting the coil body into a motor housing of the surgical instrument.2. The method of claim 1, wherein the plurality of sets of wires arewrapped on the plurality of sets of pins such that: the coils in each ofthe plurality of phase sets are at respective positions about the rod;and one of the plurality of sets of wires comprises at least threewires.
 3. The method of claim 1, wherein the wrapping of the pluralityof sets of wires on the plurality of sets of pins comprises: wrapping afirst set of wires on a first group of pins to form a first phase set,wherein the plurality of sets of pins comprise the first group of pins,a second group of pins, and a third group of pins; wrapping a second setof wires on the second group of pins to form a second phase set; andwrapping a third set of wires on the third group of pins to form a thirdphase set.
 4. The method of claim 3, wherein each of the plurality ofsets of wires are wrapped on the plurality of pins such that (i) theplurality of coils of each of the plurality of phase sets are 180°out-of-phase from each other relative to the rod, and (ii) each of theplurality of phase sets are at 120° out-of-phase from each otherrelative to the rod.
 5. The method of claim 1, wherein each of theplurality of sets of wires are wrapped on the plurality of pins suchthat (i) the plurality of coils of each of the plurality of phase setsare positioned opposite each other at 180° intervals about the rod, and(ii) the plurality of phase sets are positioned about the rod at 120°intervals.
 6. The method of claim 1, further comprising: prior tocompressing the coil body a first time, applying a first protectivelayer to the coil body; removing the first protective layer subsequentto compressing the coil body a first time; applying a second protectivelayer to the coil body subsequent to compressing the coil body a firsttime; and inserting the portion of the coil body with a correspondingportion of the second protective layer in the sleeve.
 7. The method ofclaim 1, further comprising: subsequent to compressing the coil by asecond time, rotating the coil body in a press; and compressing the coilbody a third time.
 8. The method of claim 1, further comprising:measuring first resistances of the plurality of sets of wires prior tothe fusing of the plurality of sets of wires the first time; measuringsecond resistances of the plurality of sets of wires subsequent to thefusing of the plurality of sets of wires the second time; comparing thefirst resistances to the second resistances; and determining whether oneof the plurality of phase sets is damaged based on results of thecomparing of the first resistances to the second resistances.
 9. Themethod of claim 1, further comprising: applying a thermocouple to thecoil body; monitoring a temperature of the coil body during the fusingof the plurality of wires the first time and the fusing of the pluralityof wires the second time; and controlling an amount of current suppliedto the plurality of phase sets based on the temperature.
 10. A method ofmanufacturing a motor for a surgical instrument, the method comprising:wrapping a first set of wires on a first and second set of pins to forma first coil in a first phase set; wrapping the first set of wires onthe first and second sets of pins to form a second coil in the firstphase set; removing the first set of pins from a rod; compressing afirst portion of the first and second coils of the first phase set;removing the second set of pins from the rod; compressing a secondportion of the first and second coils of the first phase set; insertingthe first and second coils of the first phase set into a sleeve; andcompressing the sleeve and the first and second coils of the first phaseset.
 11. The method of claim 10, further comprising inserting the firstphase set having the first and second coils into a motor housing of thesurgical instrument.
 12. The method of claim 10, further comprisingremoving the first and second coils of the first phase set from the rod.13. The method of claim 10, wherein the first set of wires comprises atleast three wires.
 14. The method of claim 10, further comprisingapplying a bonding agent to the first set of wires prior to wrapping toaid in fusing the wires together.
 15. The method of claim 10, furthercomprising wrapping a second set of wires on the first and second set ofpins to form a second phase set having a third coil and a fourth coil.16. The method of claim 15, further comprising: connecting the firstphase set and the second phase set in series; and applying current tothe first and second phase sets to fuse the first and second phase sets.17. The method of claim 15, further comprising wrapping a third set ofwires on the first and second set of pins to form a third phase sethaving a fifth coil and a sixth coil.
 18. The method of claim 10,wherein the first coil is 180° out-of-phase from the second coilrelative to the rod.
 19. The method of claim 16, further comprising:applying a thermocouple to a coil body formed from the first and secondphase sets; monitoring a temperature of the coil body during the fusingof the first and second phase sets; and controlling an amount of currentsupplied to the first and second phase sets based on the temperature.20. The method of claim 16, further comprising: measuring a firstresistance of the first and second phase sets prior to fusing; measuringa second resistance of the first and second phase sets subsequent tofusing; comparing the first resistances to the second resistances; anddetermining whether one of the phase sets is damaged based on results ofthe comparing of the first resistances to the second resistances.